re PR fortran/90903 (Implement runtime checks for bit manipulation intrinsics)

2019-07-16  Harald Anlauf  <anlauf@gmx.de>

	PR fortran/90903
	* libgfortran.h: Add mask for -fcheck=bits option.
	* options.c (gfc_handle_runtime_check_option): Add option "bits"
	to run-time checks selectable via -fcheck.
	* trans-intrinsic.c (gfc_conv_intrinsic_btest)
	(gfc_conv_intrinsic_singlebitop, gfc_conv_intrinsic_ibits)
	(gfc_conv_intrinsic_shift, gfc_conv_intrinsic_ishft)
	(gfc_conv_intrinsic_ishftc): Implement run-time checks for the
	POS, LEN, SHIFT, and SIZE arguments.
	* gfortran.texi: Document run-time checks for bit manipulation
	intrinsics.
	* invoke.texi: Document new -fcheck=bits option.

	PR fortran/90903
	* gfortran.dg/check_bits_1.f90: New testcase.

From-SVN: r273535

gcc/fortran/ChangeLog

+2019-07-16  Harald Anlauf  <anlauf@gmx.de>
+
+	PR fortran/90903
+	* libgfortran.h: Add mask for -fcheck=bits option.
+	* options.c (gfc_handle_runtime_check_option): Add option "bits"
+	to run-time checks selectable via -fcheck.
+	* trans-intrinsic.c (gfc_conv_intrinsic_btest)
+	(gfc_conv_intrinsic_singlebitop, gfc_conv_intrinsic_ibits)
+	(gfc_conv_intrinsic_shift, gfc_conv_intrinsic_ishft)
+	(gfc_conv_intrinsic_ishftc): Implement run-time checks for the
+	POS, LEN, SHIFT, and SIZE arguments.
+	* gfortran.texi: Document run-time checks for bit manipulation
+	intrinsics.
+	* invoke.texi: Document new -fcheck=bits option.
+
 2019-07-14  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR fortran/87233

gcc/fortran/gfortran.texi

@@ -3790,7 +3790,8 @@ initialization using @code{_gfortran_set_args}.
 Default: enabled.
 @item @var{option}[6] @tab Enables run-time checking.  Possible values
 are (bitwise or-ed): GFC_RTCHECK_BOUNDS (1), GFC_RTCHECK_ARRAY_TEMPS (2),
-GFC_RTCHECK_RECURSION (4), GFC_RTCHECK_DO (16), GFC_RTCHECK_POINTER (32).
+GFC_RTCHECK_RECURSION (4), GFC_RTCHECK_DO (16), GFC_RTCHECK_POINTER (32),
+GFC_RTCHECK_BITS (64).
 Default: disabled.
 @item @var{option}[7] @tab Unused.
 @item @var{option}[8] @tab Show a warning when invoking @code{STOP} and

gcc/fortran/invoke.texi

@@ -183,7 +183,7 @@ and warnings}.
 @gccoptlist{-faggressive-function-elimination -fblas-matmul-limit=@var{n} @gol
 -fbounds-check -ftail-call-workaround -ftail-call-workaround=@var{n} @gol
 -fcheck-array-temporaries @gol
--fcheck=@var{<all|array-temps|bounds|do|mem|pointer|recursion>} @gol
+-fcheck=@var{<all|array-temps|bits|bounds|do|mem|pointer|recursion>} @gol
 -fcoarray=@var{<none|single|lib>} -fexternal-blas -ff2c
 -ffrontend-loop-interchange @gol
 -ffrontend-optimize @gol
@@ -1558,6 +1558,7 @@ library needs to be linked.
 @item -fcheck=@var{<keyword>}
 @opindex @code{fcheck}
 @cindex array, bounds checking
+@cindex bit intrinsics checking
 @cindex bounds checking
 @cindex pointer checking
 @cindex memory checking
@@ -1582,6 +1583,10 @@ sometimes useful in optimization, in order to avoid such temporaries.
 
 Note: The warning is only printed once per location.
 
+@item @samp{bits}
+Enable generation of run-time checks for invalid arguments to the bit
+manipulation intrinsics.
+
 @item @samp{bounds}
 Enable generation of run-time checks for array subscripts
 and against the declared minimum and maximum values.  It also

gcc/fortran/libgfortran.h

@@ -73,9 +73,11 @@ along with GCC; see the file COPYING3.  If not see
 #define GFC_RTCHECK_DO          (1<<3)
 #define GFC_RTCHECK_POINTER     (1<<4)
 #define GFC_RTCHECK_MEM         (1<<5)
+#define GFC_RTCHECK_BITS        (1<<6)
 #define GFC_RTCHECK_ALL        (GFC_RTCHECK_BOUNDS | GFC_RTCHECK_ARRAY_TEMPS \
 				| GFC_RTCHECK_RECURSION | GFC_RTCHECK_DO \
-				| GFC_RTCHECK_POINTER | GFC_RTCHECK_MEM)
+				| GFC_RTCHECK_POINTER | GFC_RTCHECK_MEM \
+				| GFC_RTCHECK_BITS)
 
 /* Special unit numbers used to convey certain conditions.  Numbers -4
    thru -9 available.  NEWUNIT values start at -10.  */

gcc/fortran/options.c

@@ -580,12 +580,12 @@ gfc_handle_runtime_check_option (const char *arg)
   int result, pos = 0, n;
   static const char * const optname[] = { "all", "bounds", "array-temps",
 					  "recursion", "do", "pointer",
-					  "mem", NULL };
+					  "mem", "bits", NULL };
   static const int optmask[] = { GFC_RTCHECK_ALL, GFC_RTCHECK_BOUNDS,
 				 GFC_RTCHECK_ARRAY_TEMPS,
 				 GFC_RTCHECK_RECURSION, GFC_RTCHECK_DO,
 				 GFC_RTCHECK_POINTER, GFC_RTCHECK_MEM,
-				 0 };
+				 GFC_RTCHECK_BITS, 0 };
  
   while (*arg)
     {

gcc/fortran/trans-intrinsic.c

@@ -6166,6 +6166,24 @@ gfc_conv_intrinsic_btest (gfc_se * se, gfc_expr * expr)
   gfc_conv_intrinsic_function_args (se, expr, args, 2);
   type = TREE_TYPE (args[0]);
 
+  /* Optionally generate code for runtime argument check.  */
+  if (gfc_option.rtcheck & GFC_RTCHECK_BITS)
+    {
+      tree below = fold_build2_loc (input_location, LT_EXPR,
+				    logical_type_node, args[1],
+				    build_int_cst (TREE_TYPE (args[1]), 0));
+      tree nbits = build_int_cst (TREE_TYPE (args[1]), TYPE_PRECISION (type));
+      tree above = fold_build2_loc (input_location, GE_EXPR,
+				    logical_type_node, args[1], nbits);
+      tree scond = fold_build2_loc (input_location, TRUTH_ORIF_EXPR,
+				    logical_type_node, below, above);
+      gfc_trans_runtime_check (true, false, scond, &se->pre, &expr->where,
+			       "POS argument (%ld) out of range 0:%ld "
+			       "in intrinsic BTEST",
+			       fold_convert (long_integer_type_node, args[1]),
+			       fold_convert (long_integer_type_node, nbits));
+    }
+
   tmp = fold_build2_loc (input_location, LSHIFT_EXPR, type,
 			 build_int_cst (type, 1), args[1]);
   tmp = fold_build2_loc (input_location, BIT_AND_EXPR, type, args[0], tmp);
@@ -6236,6 +6254,32 @@ gfc_conv_intrinsic_singlebitop (gfc_se * se, gfc_expr * expr, int set)
   gfc_conv_intrinsic_function_args (se, expr, args, 2);
   type = TREE_TYPE (args[0]);
 
+  /* Optionally generate code for runtime argument check.  */
+  if (gfc_option.rtcheck & GFC_RTCHECK_BITS)
+    {
+      tree below = fold_build2_loc (input_location, LT_EXPR,
+				    logical_type_node, args[1],
+				    build_int_cst (TREE_TYPE (args[1]), 0));
+      tree nbits = build_int_cst (TREE_TYPE (args[1]), TYPE_PRECISION (type));
+      tree above = fold_build2_loc (input_location, GE_EXPR,
+				    logical_type_node, args[1], nbits);
+      tree scond = fold_build2_loc (input_location, TRUTH_ORIF_EXPR,
+				    logical_type_node, below, above);
+      size_t len_name = strlen (expr->value.function.isym->name);
+      char *name = XALLOCAVEC (char, len_name + 1);
+      for (size_t i = 0; i < len_name; i++)
+	name[i] = TOUPPER (expr->value.function.isym->name[i]);
+      name[len_name] = '\0';
+      tree iname = gfc_build_addr_expr (pchar_type_node,
+					gfc_build_cstring_const (name));
+      gfc_trans_runtime_check (true, false, scond, &se->pre, &expr->where,
+			       "POS argument (%ld) out of range 0:%ld "
+			       "in intrinsic %s",
+			       fold_convert (long_integer_type_node, args[1]),
+			       fold_convert (long_integer_type_node, nbits),
+			       iname);
+    }
+
   tmp = fold_build2_loc (input_location, LSHIFT_EXPR, type,
 			 build_int_cst (type, 1), args[1]);
   if (set)
@@ -6261,6 +6305,42 @@ gfc_conv_intrinsic_ibits (gfc_se * se, gfc_expr * expr)
   gfc_conv_intrinsic_function_args (se, expr, args, 3);
   type = TREE_TYPE (args[0]);
 
+  /* Optionally generate code for runtime argument check.  */
+  if (gfc_option.rtcheck & GFC_RTCHECK_BITS)
+    {
+      tree tmp1 = fold_convert (long_integer_type_node, args[1]);
+      tree tmp2 = fold_convert (long_integer_type_node, args[2]);
+      tree nbits = build_int_cst (long_integer_type_node,
+				  TYPE_PRECISION (type));
+      tree below = fold_build2_loc (input_location, LT_EXPR,
+				    logical_type_node, args[1],
+				    build_int_cst (TREE_TYPE (args[1]), 0));
+      tree above = fold_build2_loc (input_location, GT_EXPR,
+				    logical_type_node, tmp1, nbits);
+      tree scond = fold_build2_loc (input_location, TRUTH_ORIF_EXPR,
+				    logical_type_node, below, above);
+      gfc_trans_runtime_check (true, false, scond, &se->pre, &expr->where,
+			       "POS argument (%ld) out of range 0:%ld "
+			       "in intrinsic IBITS", tmp1, nbits);
+      below = fold_build2_loc (input_location, LT_EXPR,
+			       logical_type_node, args[2],
+			       build_int_cst (TREE_TYPE (args[2]), 0));
+      above = fold_build2_loc (input_location, GT_EXPR,
+			       logical_type_node, tmp2, nbits);
+      scond = fold_build2_loc (input_location, TRUTH_ORIF_EXPR,
+			       logical_type_node, below, above);
+      gfc_trans_runtime_check (true, false, scond, &se->pre, &expr->where,
+			       "LEN argument (%ld) out of range 0:%ld "
+			       "in intrinsic IBITS", tmp2, nbits);
+      above = fold_build2_loc (input_location, PLUS_EXPR,
+			       long_integer_type_node, tmp1, tmp2);
+      scond = fold_build2_loc (input_location, GT_EXPR,
+			       logical_type_node, above, nbits);
+      gfc_trans_runtime_check (true, false, scond, &se->pre, &expr->where,
+			       "POS(%ld)+LEN(%ld)>BIT_SIZE(%ld) "
+			       "in intrinsic IBITS", tmp1, tmp2, nbits);
+    }
+
   mask = build_int_cst (type, -1);
   mask = fold_build2_loc (input_location, LSHIFT_EXPR, type, mask, args[2]);
   mask = fold_build1_loc (input_location, BIT_NOT_EXPR, type, mask);
@@ -6382,6 +6462,32 @@ gfc_conv_intrinsic_shift (gfc_se * se, gfc_expr * expr, bool right_shift,
      gcc requires a shift width < BIT_SIZE(I), so we have to catch this
      special case.  */
   num_bits = build_int_cst (TREE_TYPE (args[1]), TYPE_PRECISION (type));
+
+  /* Optionally generate code for runtime argument check.  */
+  if (gfc_option.rtcheck & GFC_RTCHECK_BITS)
+    {
+      tree below = fold_build2_loc (input_location, LT_EXPR,
+				    logical_type_node, args[1],
+				    build_int_cst (TREE_TYPE (args[1]), 0));
+      tree above = fold_build2_loc (input_location, GT_EXPR,
+				    logical_type_node, args[1], num_bits);
+      tree scond = fold_build2_loc (input_location, TRUTH_ORIF_EXPR,
+				    logical_type_node, below, above);
+      size_t len_name = strlen (expr->value.function.isym->name);
+      char *name = XALLOCAVEC (char, len_name + 1);
+      for (size_t i = 0; i < len_name; i++)
+	name[i] = TOUPPER (expr->value.function.isym->name[i]);
+      name[len_name] = '\0';
+      tree iname = gfc_build_addr_expr (pchar_type_node,
+					gfc_build_cstring_const (name));
+      gfc_trans_runtime_check (true, false, scond, &se->pre, &expr->where,
+			       "SHIFT argument (%ld) out of range 0:%ld "
+			       "in intrinsic %s",
+			       fold_convert (long_integer_type_node, args[1]),
+			       fold_convert (long_integer_type_node, num_bits),
+			       iname);
+    }
+
   cond = fold_build2_loc (input_location, GE_EXPR, logical_type_node,
 			  args[1], num_bits);
 
@@ -6436,6 +6542,20 @@ gfc_conv_intrinsic_ishft (gfc_se * se, gfc_expr * expr)
      gcc requires a shift width < BIT_SIZE(I), so we have to catch this
      special case.  */
   num_bits = build_int_cst (TREE_TYPE (args[1]), TYPE_PRECISION (type));
+
+  /* Optionally generate code for runtime argument check.  */
+  if (gfc_option.rtcheck & GFC_RTCHECK_BITS)
+    {
+      tree outside = fold_build2_loc (input_location, GT_EXPR,
+				    logical_type_node, width, num_bits);
+      gfc_trans_runtime_check (true, false, outside, &se->pre, &expr->where,
+			       "SHIFT argument (%ld) out of range -%ld:%ld "
+			       "in intrinsic ISHFT",
+			       fold_convert (long_integer_type_node, args[1]),
+			       fold_convert (long_integer_type_node, num_bits),
+			       fold_convert (long_integer_type_node, num_bits));
+    }
+
   cond = fold_build2_loc (input_location, GE_EXPR, logical_type_node, width,
 			  num_bits);
   se->expr = fold_build3_loc (input_location, COND_EXPR, type, cond,
@@ -6454,6 +6574,7 @@ gfc_conv_intrinsic_ishftc (gfc_se * se, gfc_expr * expr)
   tree lrot;
   tree rrot;
   tree zero;
+  tree nbits;
   unsigned int num_args;
 
   num_args = gfc_intrinsic_argument_list_length (expr);
@@ -6461,12 +6582,14 @@ gfc_conv_intrinsic_ishftc (gfc_se * se, gfc_expr * expr)
 
   gfc_conv_intrinsic_function_args (se, expr, args, num_args);
 
+  type = TREE_TYPE (args[0]);
+  nbits = build_int_cst (long_integer_type_node, TYPE_PRECISION (type));
+
   if (num_args == 3)
     {
       /* Use a library function for the 3 parameter version.  */
       tree int4type = gfc_get_int_type (4);
 
-      type = TREE_TYPE (args[0]);
       /* We convert the first argument to at least 4 bytes, and
 	 convert back afterwards.  This removes the need for library
 	 functions for all argument sizes, and function will be
@@ -6480,6 +6603,32 @@ gfc_conv_intrinsic_ishftc (gfc_se * se, gfc_expr * expr)
       args[1] = convert (int4type, args[1]);
       args[2] = convert (int4type, args[2]);
 
+      /* Optionally generate code for runtime argument check.  */
+      if (gfc_option.rtcheck & GFC_RTCHECK_BITS)
+	{
+	  tree size = fold_convert (long_integer_type_node, args[2]);
+	  tree below = fold_build2_loc (input_location, LE_EXPR,
+					logical_type_node, size,
+					build_int_cst (TREE_TYPE (args[1]), 0));
+	  tree above = fold_build2_loc (input_location, GT_EXPR,
+					logical_type_node, size, nbits);
+	  tree scond = fold_build2_loc (input_location, TRUTH_ORIF_EXPR,
+					logical_type_node, below, above);
+	  gfc_trans_runtime_check (true, false, scond, &se->pre, &expr->where,
+				   "SIZE argument (%ld) out of range 1:%ld "
+				   "in intrinsic ISHFTC", size, nbits);
+	  tree width = fold_convert (long_integer_type_node, args[1]);
+	  width = fold_build1_loc (input_location, ABS_EXPR,
+				   long_integer_type_node, width);
+	  scond = fold_build2_loc (input_location, GT_EXPR,
+				   logical_type_node, width, size);
+	  gfc_trans_runtime_check (true, false, scond, &se->pre, &expr->where,
+				   "SHIFT argument (%ld) out of range -%ld:%ld "
+				   "in intrinsic ISHFTC",
+				   fold_convert (long_integer_type_node, args[1]),
+				   size, size);
+	}
+
       switch (expr->ts.kind)
 	{
 	case 1:
@@ -6505,12 +6654,26 @@ gfc_conv_intrinsic_ishftc (gfc_se * se, gfc_expr * expr)
 
       return;
     }
-  type = TREE_TYPE (args[0]);
 
   /* Evaluate arguments only once.  */
   args[0] = gfc_evaluate_now (args[0], &se->pre);
   args[1] = gfc_evaluate_now (args[1], &se->pre);
 
+  /* Optionally generate code for runtime argument check.  */
+  if (gfc_option.rtcheck & GFC_RTCHECK_BITS)
+    {
+      tree width = fold_convert (long_integer_type_node, args[1]);
+      width = fold_build1_loc (input_location, ABS_EXPR,
+			       long_integer_type_node, width);
+      tree outside = fold_build2_loc (input_location, GT_EXPR,
+				      logical_type_node, width, nbits);
+      gfc_trans_runtime_check (true, false, outside, &se->pre, &expr->where,
+			       "SHIFT argument (%ld) out of range -%ld:%ld "
+			       "in intrinsic ISHFTC",
+			       fold_convert (long_integer_type_node, args[1]),
+			       nbits, nbits);
+    }
+
   /* Rotate left if positive.  */
   lrot = fold_build2_loc (input_location, LROTATE_EXPR, type, args[0], args[1]);
 

gcc/testsuite/ChangeLog

+2019-07-16  Harald Anlauf  <anlauf@gmx.de>
+
+	PR fortran/90903
+	* gfortran.dg/check_bits_1.f90: New testcase.
+
 2019-07-16  Jeff Law  <law@redhat.com>
 
 	PR rtl-optimization/91173

gcc/testsuite/gfortran.dg/check_bits_1.f90

+! { dg-do run }
+! { dg-options "-fcheck=bits -fdump-tree-original" }
+! { dg-shouldfail "Fortran runtime error: SIZE argument (0) out of range 1:32 in intrinsic ISHFTC" }
+! { dg-output "At line 44 .*" }
+!
+! Verify that the runtime checks for the bit manipulation intrinsic functions
+! do not generate false-positives
+program check
+  implicit none
+  integer :: i, k, pos, len, shift, size, nb
+  nb = bit_size (i)
+  i = 0
+  do pos = 0, nb-1
+     k = ibset (i, pos)
+     i = ibclr (k, pos)
+     if (btest (i, pos)) stop 1
+  end do
+  do pos = 0, nb
+     do len = 0, nb-pos
+        i = ibits (i, pos, len)
+     end do
+  end do
+  do shift = 0, nb
+     k = ishft (i,  shift)
+     i = ishft (k, -shift)
+  end do
+  do shift = 0, nb
+     k = shiftl (i, shift) ! Fortran 2008
+     i = shiftr (k, shift)
+     i = shifta (i, shift)
+     k = lshift (i, shift) ! GNU extensions
+     i = rshift (k, shift)
+  end do
+  do shift = 0, nb
+     k = ishftc (i,  shift)
+     i = ishftc (k, -shift)
+     do size = max (1,shift), nb
+        k = ishftc (i,  shift, size)
+        i = ishftc (k, -shift, size)
+     end do
+  end do
+  size = 0
+  ! The following line should fail with a runtime error:
+  k = ishftc (i, 0, size)
+  ! Should never get here with -fcheck=bits
+  stop 2
+end program check
+
+! { dg-final { scan-tree-dump-times "_gfortran_runtime_error_at" 21 "original" } }